1. Field of the Invention
The present invention relates to material pattern, and mold using thereof, metal thin-film pattern, metal pattern, and method of forming the sames, and more specially to polymer or resist pattern, and mold using thereof, metal thin-film pattern, metal pattern, and method of forming the sames.
2. Description of the Background Art
In general, for configuring a metal wiring in a circuit device such as semiconductor, first a polymer pattern having a predetermined shape should be formed. Such a polymer pattern is formed through a photolithography process including a photoresist coating process, an exposure process, and a development process.
FIG. 1 represents sequentially a method of forming a photosensitive polymer pattern using a conventional lithography process.
As shown in FIG. 1, a photoresist made of polymer is coated on a substrate 100 to form a photoresist film. A photomask 120 is arranged in the upper part of the photoresist film 110. A light 130 is selectively projected on the substrate 100 where the photoresist film 110 is formed to perform the exposure process. After performing the exposure process, by performing the development process on the exposed photoresist film 110, a part of the photoresist film 110 reacted to the light is eliminated to form the polymer pattern.
The photosensitive polymer or resist film is exposed by Ultraviolet-UV passing a photomask having a pattern of geometric figure and a projection of the rest light in a general lithography process of a semiconductor. The exposed section is formed by a required pattern through a development process of the exposed section. In case of using a positive photosensitive resist, a section exposed by light is melted by a development solution and forms a pattern. In case of using a negative photosensitive resist, a section unexposed by light is melted by a development solution and forms a pattern.
FIG. 2 represents a cross-section of a photosensitive polymer, a resist pattern and a metal pattern manufactured by a lithography process of the related art.
As shown in FIG. 2, a cross section of a polymer or a resist pattern projects the light perpendicular to the substrate during the exposure process where the light is projected on the substrate, thus a pattern of a polymer or a resist is formed from a perpendicular structure of rectangular shape. S. Wolf and R. N. Tauber, “Silicon Processing for the VLSI Era, Volume 1—Process Technology”, Lattice Press, pp. 408, 1986.
Accordingly, a metal wiring in a VLSI device using a polymer pattern having a rectangular cross-section also forms on the polymer pattern, thus a metal pattern having a rectangular cross-section shape is formed. R. C. Jaeger, “Introduction to Microelectronic Fabrication”, Prentice Hall, pp. 167, 2002.
However, the conventional polymer pattern or metal pattern having the rectangular shape or the metal pattern can not satisfy the need on various patterns having three-dimensional structure devices. The various techniques for the semiconductor are developed and the applied field thereof is varied, thus it needs for three-dimensional structure of polymer pattern or metal pattern, etc. having an inclined shape in difference with the conventional technique.
Various techniques of lithography are developed for manufacturing three-dimensional structure and shape. As for the technique of inclined lithography being usable for forming an inclined structure in the perpendicular direction, it is applied variously to manufacture the microscopic material system. Contrary to a general photolithography exposure using a parallel light incident in a perpendicular direction in a photomask and substrate, as illustrated in FIG. 3(a), it has a constant angle θ in a photomask 160 and substrate 150, and it uses the parallel light 170 incident in the inclined direction to expose. Consequently, it can form a pattern of shape inclined with a constant angle. In case of left side 180, it is a positive photo-sensitive photoresist that the exposed section is removed, and the unexposed section is left. In case of right side 181, it is a negative photo-sensitive photoresist that the exposed section is left, and the unexposed section is removed. A papers “H. Sato, T. Kakinuma, J. S. Go, S. Shoji “In-channel 3-D micromesh structures using maskless multi-angle exposures and their microfilter application” (Sen. Actuators A, vol. 111, pp. 87-92, 2004)” and R. Yang, J. D. Williams, and W. Wang, “A rapid micro-mixer/reactor based on arrays of spatially impinging micro-jets” (J. Micromech. Microeng., vol. 14, pp. 1345-1351, 2004) record examples to make a movement route of the microscope materiality and manufacturing a filter, etc. by using the technique of inclined lithography.
Also, in order to manufacture an inclined structure of more complex three-dimensional shape by applying the technique of inclined lithography, the technique exposing with rotating a light source with a fixed plate and the technique exposing with rotating a photomask and a stage where the substrate are putted a light source with a fixed plate are developed. These techniques expose a few times by rotating freely the light source and substrate and manufacture a pattern of various shapes of three-dimensional curved surface.
The inclined/rotating technique rotating a substrate with a fixed light source (reference: Y.-K. Yoon, J.-H. Park, and M. G. Allen, “Multidirectional UV lithography for complex 3-D MEMS structures”, J. Microelectromech. Syst., vol. 15, pp. 1121-1130, 2006) and the technique for lithography having various directions (reference: Y.-K. Yoon, J.-H. Park, and M. G. Allen, “Multidirectional UV lithography for complex 3-D MEMS structures”, J. Microelectromech. Syst., vol. 15, pp. 1121-1130, 2006) are used representatively. FIG. 3(b) is a device for special lithography so as to expose with rotating in reference to the paper of Y.-K. Yoon. It rotates a substrate by a rotated stage 190 and exposures to inclined shape, thus it manufactures three-dimensional pattern.
Consequently, these methods have a problem that is required for special device for lithography preparing a device rotating a light source to expose or a device rotating the stage where an exposed substrate or a substrate is putted. Accordingly, in order to make an inclined shape of three-dimension, it is required for a lithography device which can rotate an ultraviolet rays or substrate. Also, in order to make an inclined structure having a complex shape, it is difficult to change a sequential inclination angle by using a device which can control for rotating an ultraviolet rays or substrate to rotate.
Additionally, a method of lithography for forming a pattern of three-dimensional shape on a polymer or a resist is developed as follows. As illustrated in FIG. 4, according to the patent right No. 10-0649937 of the republic of korea (i.e., a method of forming polymer pattern and metal thin film using thereof, metal pattern, plastic mold structure and method of forming the sames), it forms polymer film 201 on the substrate 200 and forms a polymer pattern 206, 207 of circular cross-section by passing an arbitrary progressing light through photomask 202. It uses a method that it puts a diffuser sheet 208 in a route of exposing and progresses the light exposed on polymer by dispersing light in an arbitrary direction. It can manufacture a polymer pattern having three-dimensional shape and various metal patterns, etc.
As illustrated in FIG. 5, according to the patent registration No. 10-0649937 filed in korea (i.e., a method of forming polymer pattern and metal thin film using thereof, metal pattern, plastic mold and method of forming the sames), it can manufacture a pattern of various three-dimensional shapes from a circular shape to a rectangular shape. It forms a polymer or a resist film 310 on the substrate 300 and disposes a photomask 320, and thus it forms a section which will be exposed and unexposed 350, 351, and it puts a controlling film of light 340 at a route of exposing. Also, it can control variously a shape exposed on a polymer or a resist from a circular shape 353, 354 to a rectangular shape 355 by a method of controlling a progressing character of light or strength.
It can form simply the structure of three-dimensional shape by above two inventions. However, it controls symmetrically the progress direction of light on the space in case of a polymer dispersed liquid crystal film representing the control film of light for controlling a progress direction of light and the diffuser dispersing the light for exposing. Accordingly, the manufactured three-dimensional shape has only a structure of symmetric space. Consequently, there is a problem that it can not form a polymer or a resist pattern of three-dimensional symmetric structure having an inclined shape with a specific angle for various applications.